Abstract:

Two ash-less and phosphorous-free nitrogen-containing heterocyclic anti-wear additives (N-di-isooctyl-2-benzothiazolesulfenamide, DIMB and (2-sulfurone-benzothiazole)-3-methyl-isooctyl thiohydroxy acetate, MBES) were synthesized. Their anti-wear and friction-reduction performances as lubricating oil additives in group Ⅲ base oil were evaluated using SRV high temperature friction and wear tester. The chemistry of their tribofilms was analyzed with X-ray absorption near-edge spectroscopy (XANES), and atomic force microscopy (AFM) was then used to examine the general morphology of the reaction films. The results showed that the two nitrogen-containing heterocyclic compounds possess rather od anti-wear properties, but no friction-reducing performance. According to the XANES analytic results, the tribofilms generated from the additive MBES were mainly composed of FeSO4, whereas the films generated fromthe additive DIMB mainly contained FeS2. The AFMimages revealed that in comparison with the worn surfaces fromzinc dialkyldithiophosphate (ZDDP), the worn surfaces fromthe additives DIMB and MBES, respectively, presented large and deep grooves.